We investigate the electron and hole spin relaxation in an ensemble of self-assembled InAs/In0.53Al0.24Ga0.23As/InP quantum dots with emission wavelengths around 1.5~μm by pump-probe Faraday rotation spectroscopy. Electron spin dephasing due to the randomly oriented nuclear Overhauser fields is observed. At low temperatures we find a sub-microsecond longitudinal electron spin relaxation time T1 which unexpectedly strongly depends on temperature. At high temperatures the electron spin relaxation time is limited by optical phonon scattering through spin-orbit interaction decreasing down to 0.1~ns at 260~K. We show that the hole spin relaxation is activated much more effectively by a temperature increase compared to the electrons.
@article{arxiv.1806.10515,
title = {Electron and hole spin relaxation in InP-based self-assembled quantum dots emitting at telecom wavelengths},
author = {A. V. Mikhailov and V. V. Belykh and D. R. Yakovlev and P. S. Grigoryev and J. P. Reithmaier and M. Benyoucef and M. Bayer},
journal= {arXiv preprint arXiv:1806.10515},
year = {2019}
}